1. Field of the Invention
The present invention relates to an unloader mechanism for removing a cured tire from a vulcanizing machine, and more particularly an improved unloader capable of removing the tire without the assistance of a bag well unit which has been customarily required for unloading the tire from the machine.
2. Description of the Prior Art
A typical vulcanizing machine includes a pair of upper movable and lower stationary molds and a central bag well unit being disposed centrally in the lower mold and having an inflatably deformable bladder. When the upper and lower molds are closed to compressingly receive a green tire therein, the bladder becomes inflated in an intimate contact with the tire interiorly thereof. Under this condition, a heated pressure medium such as high pressure steam is supplied to the inflated bladder and the molds are heated so as to vulcanize the tire. The thus vulcanized or cured tire is commonly removed from the machine according to the prior art as described hereinbelow. For instance, Japanese Patent Laid-Open Publication No. 56-148539 discloses an unloader mechanism as reillustrated in FIGS. 3A-3D of the accompanying drawings showing successive steps of the unloading operation of the mechanism.
FIG. 3A shows a vulcanizing press machine having just finished vulcanization. A movable upper mold A and a stationary lower mold B are in a closing contact with each other, and jointly hold a tire T1 therebetween. In this machine the upper mold is raised upwardly maintaining a horizontal posture thereof. A bladder 203 is supported by a central bag well mechanism C and is interiorly in intimate contact with the tire, which is heated from inside by a heated pressure medium such as a high pressure steam supplied thereinto and the two molds being heated by a suitable heat element. Designated by 391 is a tread-shaping member included in the upper mold A. Upon completion of vulcanization, the upper mold A is upwardly moved apart from the lower mold as shown in FIG. 3B. Then the bladder 203 is withdrawn from the interior of the tire T1 into the central bag well mechanism C, which is entirely raised, as shown in the drawing, to lift therewith the cured tire T1 apart from a surface of a press mold member 187 of the lower stationary mold B by retaining the tire at a lower toe ring ( i.e. lower bead ring ) 186 formed on an upper end of the central mechanism. Designated by 201 and 202 are bladder bead rings supporting upper and lower ends of the bladder 203, respectively. With the machine in this position, a substantially U-shaped unloader arm 294 is extended from outside of the machine to a position beneath the tire T1 to thereby hold the latter as shown in FIG. 3C. Designated by 295 is a stop member disposed at one end of the unloader arm 294. Holding the tire T1 thereon, the unloader arm 294 is angularly moved to thereby disengage the tire T1 from the lower toe ring 186 to lift the same off the central well mechanism 185. The unloader arm holding the tire T1 with assistance of the stop member retaining the rear end of the latter is retracted out of the press machine so as to transfer the same.
Another example of the typical known unloading mechanism is reillustrated in FIGS. 4A-4C, which show unloading steps successively. In FIG. 4A, designated by A, B, and C are an angularly movable upper mold, a stationary lower mold, and a central bag well mechanism vertically movably received centrally in the lower mold. A bladder 103 has a lower end fixedly connected to a lower bead ring 104 formed on an upper end of the central mechanism, and an upper end fixedly connected to an upper bead ring 105 movable independently of and accompanied by the central mechanism 102, the bladder being deformable inflatably.
FIG. 4A shows the vulcanizing machine in such a condition in that with the movable upper mold A having been angularly upwardly moved away from the lower mold after the vulcanization is completed, the central mechanism C is entirely moved upwardly carrying thereon the cured tire T1 which was lifted off the lower mold B through the bladder received in the tire T1, and the mechanism stops at an uppermost position where the upper bead ring 105 is solely moved upwardly to release the bladder 103 out of the tire by extending the bladder. Immediately before the releasing of the bladder, an unloader arm 106 enters the machine and reaches beneath the tire T1 to support the same. Then the central mechanism C is lowered together with the bladder 103 as shown in FIG. 4B, whereupon the unloader 106 is angularly upwardly moved through cam movement thereof, so that the tire T1 slides downwardly along the inclined upper surface of the unloader arm under support of the latter as shown in FIGS. 4B and 4C. Then the tire T1 moves onto a conveyor 107.
FIGS. 3A-3D and FIGS. 4A-4C show that an typical unloading mechanism and developed and/or improved versions thereof are also known. These prior unloaders are disadvantageous in that the unloader mechanism solely is incapable of removing or stripping the cured tire T1 directly from the lower mold B without assistance of the vertical movement of the central well mechanism C.
The foregoing unloader mechanisms have drawbacks in that the essential step of vertically moving the central bag well mechanism supporting the bladder tends to elongate the period of the press cycle accordingly, and in that the vulcanizing machine has a relatively great height because the machine should have an additional space for allowing the unloader to enter thereinto with the central mechanism raised into an upper position. Such unloader mechanism is apt to lift the tire from the bead end in misalignment with the lower mold, which will require additionally a tire guide unit for prevention of occurrence of such problem.